University of Illinois Urbana-Champaign

The design and analysis of a linear low profile ultra-wide band tightly coupled U-slot microstrip antenna array

Massoud, Ayah T

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https://hdl.handle.net/2142/122223

Description

Title
The design and analysis of a linear low profile ultra-wide band tightly coupled U-slot microstrip antenna array
Author(s)
Massoud, Ayah T
Issue Date
2023-11-21
Director of Research (if dissertation) or Advisor (if thesis)
Bernhard, Jennifer T
Doctoral Committee Chair(s)
Bernhard, Jennifer T
Committee Member(s)
  • Schutt-Aine, Jose E
  • Ilie, Raluca
  • Zhao, Yang
Department of Study
Electrical & Computer Eng
Discipline
Electrical & Computer Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Ultra-wide band arrays
  • UWB array
  • tight coupling
  • mutual coupling
  • U-slot Antenna
  • pattern null antenna
  • asymmetric arrays
  • small arrays
  • linear arrays.
Abstract
The fast-paced developments in modern communication systems have created intense pressures on antenna performance and capabilities. A class of ultra-wide band (UWB) arrays, known as tightly coupled arrays have re-emerged as the need for increasing bandwidth and data rates continues. The need for small, light, low-profile and inexpensive UWB arrays for personal, military, and telemetry applications inspired the research in this work. Microstrip antennas are good candidates for such applications, due to their extremely low profile, ease of fabrication, low cost, and compatibility to be mounted on large surfaces. However, they are resonant structures that are notoriously narrow band. Concepts of the wheeler current sheet and tightly coupled arrays are extended to achieve a novel low-profile UWB microstrip array. A multi-step approach was taken to reach the final design by separately analyzing inner and outer element performance. Design modifications are introduced at each step to incrementally increase bandwidth. Starting with a U-slot microstrip antenna with 8\% bandwidth, a single layer UWB four element 1-D array is implemented to achieve a bandwidth of more that 70\%; a result that has not been achieved with micorstrip antennas before. The array produces a consistent pattern null at broadside across the entire frequency band when all elements are fed in phase and a maximum at broadside when elements are fed out of phase. Next, a signal flow graph (SFG) model is developed for two co-planar patch antennas that includes mutual coupling between all four equivalent radiating slots. A generalized method to efficiently calculate the coupling between slots without resorting to circuit analysis is developed. Finally, a novel SFG-transmission line model that captures the tight coupling behavior is developed and the dynamics of tight coupling is characterized.
Graduation Semester
2023-12
Type of Resource
Thesis
Copyright and License Information
Copyright 2023 Ayah T. Massoud

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